Re: [PATCH v2 1/2] update-index: optionally leave skip-worktree entries alone

[Junio C Hamano <gitster@pobox.com>]

"Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
writes:

> From: Johannes Schindelin <johannes.schindelin@gmx.de>
>
> While `git update-index` mostly ignores paths referring to index entries
> whose skip-worktree bit is set, in b4d1690df11 (Teach Git to respect
> skip-worktree bit (reading part), 2009-08-20), for reasons that are not
> entirely obvious, the `--remove` option was made special: it _does_
> remove index entries even if their skip-worktree bit is set.
>
> Seeing as this behavior has been in place for a decade now, it does not
> make sense to change it.

If this were end-user facing Porcelain behaviour, even it is a
decade old, the story would have been different, but given that it
is in an obscure corner in a plumbing command, I agree that it does
not make sense to even transition the default over releases.

> +test_expect_success '--ignore-skip-worktree-entries leaves worktree alone' '
> +	test_commit geroff-me &&
> +	git update-index --skip-worktree geroff-me.t &&
> +	rm geroff-me.t &&

I do not see a need to swear with a sample file name.  It may make
sense to use words that relate to what the test is checking (e.g.
skip-me or something like that), but otherwise meaningless filenames
used in other tests (like 1, 2, etc) would be more in line with the
existing tests.

> +
> +	: ignoring the worktree &&
> +	git update-index --remove --ignore-skip-worktree-entries geroff-me.t &&
> +	git diff-index --cached --exit-code HEAD &&

HEAD has it, working tree does not, and the one in the index should
have been kept thanks to the new option added by this patch.  Makes
sense.

> +	: not ignoring the worktree, a deletion is staged &&
> +	git update-index --remove geroff-me.t &&
> +	test_must_fail git diff-index --cached --exit-code HEAD

Testing the other side of the coin (i.e. adding the new feature did
not accidentally stop the command from removing by default) is good;
"should have no difference" was a good test for the other side, but
in contrast, "should have some difference" is a very loose test when
the difference we want to see is that the particular path gets removed
and no other changes.

> +'
> +
>  #TODO test_expect_failure 'git-apply adds file' false
>  #TODO test_expect_failure 'git-apply updates file' false
>  #TODO test_expect_failure 'git-apply removes file' false